1. Field of the Invention
The invention relates to an optical microstructure plate and a mold for forming the same, and more particularly to an optical microstructure plate simultaneously having period alignment mark and universal mark.
2. Description of the Related Art
Many optical systems require multiple optical elements. Such required multiple optical elements include multiple refractive elements, multiple diffractive elements and refractive/diffractive hybrid elements. As the demand for optical components to be used in a wider variety of applications increases, the ability to efficiently produce such optical elements also increases. In forming such integrated multiple optical elements at a mass production level, the need for accurate alignment increases. Further, such alignment is critical when integrating more than one optical element.
When fabricating an optical element such as a lens plate, the alignment between the optical element substrate and the lens mold is also important. Furthermore, in conventional fabrication of micro-lens array substrates, after glue is dispensed, the substrate is pressed upon the lens mold filled with epoxy glue to form a micro-lens. As shown in FIG. 1a, air bubbles 50 can occur if the epoxy glue 30 is insufficient within the cavity 40 of the lens mold 10, resulting in poor performance of the micro-lens. To the contrary, as shown in FIG. 1b, excess epoxy glue 30 can overflow 60 the cavity 40 of the lens mold 10.
Therefore, it is necessary to develop an optical microstructure plate to improve the alignment with optical element molds and other optical microstructure plates, and an optical element mold to solve the aforementioned problems.